<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Validate
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Alpha.php 16223 2009-06-21 20:04:53Z thomas $
 */

/**
 * @see Zend_Validate_Abstract
 */
require_once 'Zend/Validate/Abstract.php';

/**
 * @category   Zend
 * @package    Zend_Validate
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Validate_Alpha extends Zend_Validate_Abstract
{
	const INVALID      = 'alphaInvalid';
	const NOT_ALPHA    = 'notAlpha';
	const STRING_EMPTY = 'stringEmpty';

	/**
	 * Whether to allow white space characters; off by default
	 *
	 * @var boolean
	 * @depreciated
	 */
	public $allowWhiteSpace;

	/**
	 * Alphabetic filter used for validation
	 *
	 * @var Zend_Filter_Alpha
	 */
	protected static $_filter = null;

	/**
	 * Validation failure message template definitions
	 *
	 * @var array
	 */
	protected $_messageTemplates = array(
	self::INVALID      => "Invalid type given, value should be a string",
	self::NOT_ALPHA    => "'%value%' has not only alphabetic characters",
	self::STRING_EMPTY => "'%value%' is an empty string"
	);

	/**
	 * Sets default option values for this instance
	 *
	 * @param  boolean $allowWhiteSpace
	 * @return void
	 */
	public function __construct($allowWhiteSpace = false)
	{
		$this->allowWhiteSpace = (boolean) $allowWhiteSpace;
	}

	/**
	 * Returns the allowWhiteSpace option
	 *
	 * @return boolean
	 */
	public function getAllowWhiteSpace()
	{
		return $this->allowWhiteSpace;
	}

	/**
	 * Sets the allowWhiteSpace option
	 *
	 * @param boolean $allowWhiteSpace
	 * @return Zend_Filter_Alpha Provides a fluent interface
	 */
	public function setAllowWhiteSpace($allowWhiteSpace)
	{
		$this->allowWhiteSpace = (boolean) $allowWhiteSpace;
		return $this;
	}

	/**
	 * Defined by Zend_Validate_Interface
	 *
	 * Returns true if and only if $value contains only alphabetic characters
	 *
	 * @param  string $value
	 * @return boolean
	 */
	public function isValid($value)
	{
		if (!is_string($value)) {
			$this->_error(self::INVALID);
			return false;
		}

		$this->_setValue($value);

		if ('' === $value) {
			$this->_error(self::STRING_EMPTY);
			return false;
		}

		if (null === self::$_filter) {
			/**
			 * @see Zend_Filter_Alpha
			 */
			require_once 'Zend/Filter/Alpha.php';
			self::$_filter = new Zend_Filter_Alpha();
		}

		self::$_filter->allowWhiteSpace = $this->allowWhiteSpace;

		if ($value !== self::$_filter->filter($value)) {
			$this->_error(self::NOT_ALPHA);
			return false;
		}

		return true;
	}

}
